Journal of Volcanology and Geothermal Research最新文献

{"title":"Feeding system beneath active volcanoes in central part of Iturup Island (Kuril Arc) inferred from local earthquake tomography","authors":"Ivan Koulakov ,&nbsp;Evgeny Ilyich Gordeev ,&nbsp;Ilyas Abkadyrov ,&nbsp;Olga Bergal-Kuvikas ,&nbsp;Danila Chebrov","doi":"10.1016/j.jvolgeores.2024.108233","DOIUrl":"10.1016/j.jvolgeores.2024.108233","url":null,"abstract":"<div><div>Iturup is the largest island of the Kuril Arc with more than 20 Holocene volcanoes of which 9 considered active. Here we investigate the central part of the island where we deployed in 2022–2023 a portable network of 12 seismic stations. The data of this network together with several permanent stations in surrounding islands were used to identify almost 300 events and to perform seismic tomography based on the picked arrival times of the P and S seismic waves. A challenging problem was that most of the events were located outside the network, and we performed careful analysis to examine the actual capacity of inversion with such data to recover seismic velocity structures below the network. In the resulting model, we found a dominating high-velocity anomaly below the central part of the study area, which is bounded by zones of low velocities and high Vp/Vs ratio collocated with two active volcano complexes (Chirip to the north and Ivan Grozny to the south). Below the third volcano, Baransky, we observe a change of the Vp/Vs ratio from high at large depths to low at shallow depth, indicating the process of degassing, which is supported by strong fumarolic activity and hydrothermal manifestations around this volcano. At depths of more than 20 km, the feeding paths from Baransky and Ivan Grozny volcanoes seem to be connected in one anomaly representing a common magma source below the center of the island. This seems to be a common feature observed below several volcanic islands, such as Tenerife and El Hierro, where the high-velocity rigid core in a central part is surrounded by low-velocity flows associated with recent volcanic manifestations.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"456 ","pages":"Article 108233"},"PeriodicalIF":2.4,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of FeTi oxide microlites on bubble nucleation in rhyolitic melts","authors":"Wade L. Aubin ,&nbsp;James E. Gardner","doi":"10.1016/j.jvolgeores.2024.108218","DOIUrl":"10.1016/j.jvolgeores.2024.108218","url":null,"abstract":"<div><div>We conducted a set of high-temperature decompression experiments to constrain the mechanisms of heterogeneous bubble nucleation in high-silica rhyolitic melt that contained 4.6–4.8 wt% H₂O. The melt was seeded with two different size fractions of magnetite crystals: 1–2 μm crystals and large crystals of 32–135 μm (long axis). The number density of bubbles (BND) that nucleated on the small crystals was found to increase from 10^6.5 to 10^8.7 cm⁻³ as H₂O increasingly supersaturated (ΔP) in the melt from 3 to 23 MPa. At ΔP &gt;23 MPs, however, the number of bubbles nucleated equals the number of small magnetite and no more nucleated with increased ΔP. At the same conditions, the number of bubbles that nucleated on the large crystals increases, from &lt;1 bubble per crystal at ΔP = 3 MPa to 14 ± 4 bubbles per crystal at 58 MPa. We thus find that ΔP has a significant influence on the mechanisms of heterogenous nucleation, but the observed increases in BND are much greater than would be predicted solely from the increase in ΔP. The discrepancy can be reconciled if there are different sites on the crystals that become activated at greater ΔP, leading to greater numbers of bubbles nucleating. The cumulative BND nucleated on small crystals, however, is capped by the number of crystals present. The BND values generated at ΔP &gt;23 MPa in our experiments overlap with those found in ∼80 % of naturally occurring pumice. Assuming our experiments are representative of natural pumice, this suggests that explosively erupted magmas either become significantly volatile supersaturated before heterogeneously nucleating bubbles, or that the number of nucleation sites in natural magmas greatly exceed 10⁹ cm⁻³.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"456 ","pages":"Article 108218"},"PeriodicalIF":2.4,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The dynamic of magmatic system and volcano hazard implications of the Damavand volcano (N. Iran) inferred from the textural data","authors":"Amir Eskandari ,&nbsp;Sadraddin Amini ,&nbsp;Behnam Sadeghi","doi":"10.1016/j.jvolgeores.2024.108220","DOIUrl":"10.1016/j.jvolgeores.2024.108220","url":null,"abstract":"<div><div>The Damavand stratovolcano (N Iran) consists mainly of lavas with trachyandesite-trachyte composition, and subordinate pyroclastic deposits. The intensity of explosive eruptions and the volume of pyroclastic deposits have increased over time, which may be related to increasing viscosity due to the development of crystal-rich magmas. This research integrates microanalytical and quantitative textural measurements to understand the textural evolutions from the old to the young lavas and their relationships with the physical processes occurred in the plumbing system. Age-constrained samples from the lavas were analyzed using crystal size distribution (CSD), the newly proposed multifractal analysis, including the Number-Length of crystals (N-LoC) and the Number-Area of crystals (N-AoC), along with mineral chemistry. Three to five populations of feldspars can be identified, which have undergone evolution and coarsening over time. We propose a textural development sequence established at mid to shallow crustal levels, involving several physicochemical processes, such as cycles of polybaric differentiation and episodic magma recharge into the crystal-rich magma chambers. This, in turn, caused disaggregation of crystal mushes and textural coarsening due to crystal aggregation and temperature cycling. The increasing population of microphenocrysts in younger lavas may be linked to pulsating groundmass crystallization resulting from degassing at a newly formed shallow chamber (0.5–1 kbar) beneath the young cone. The final stages of crystallization occurred during multi-step decompression in the conduits. The comparison of age data from lava samples and their stratigraphic positions suggests that triggering groundmass crystallization might have caused shifts in eruptive behavior.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"456 ","pages":"Article 108220"},"PeriodicalIF":2.4,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental constraints on the behaviour of sulphur in the 2021 Cumbre Vieja (La Palma) basanite","authors":"Diletta Frascerra ,&nbsp;Bruno Scaillet ,&nbsp;Joan Andújar ,&nbsp;Clive Oppenheimer ,&nbsp;Stéphane Scaillet ,&nbsp;Joan Martí ,&nbsp;Ramón Casillas ,&nbsp;Carmen López","doi":"10.1016/j.jvolgeores.2024.108219","DOIUrl":"10.1016/j.jvolgeores.2024.108219","url":null,"abstract":"<div><div>We performed experiments to constrain the effects of sulphur and oxygen fugacities on magma chamber and outgassing conditions of the La Palma 2021 eruption. Based on a series of controlled experiments on basanitic products carried out at 1040 °C and 200 MPa, we show that sulphur addition affects the stabilities of amphibole and olivine, in particular at high <em>f</em>O₂ and elevated S contents which together inhibit amphibole crystallization. We also show that the overriding control on S systematics is oxygen fugacity, with melts capable of dissolving from 1000 up to 8000 ppm S, depending on <em>f</em>O₂. Increasing the bulk S content increases the S content of the silicate melt up to ∼2000 ppm for <em>f</em>O₂ &lt; NNO + 2, and 7000–8000 ppm at higher <em>f</em>O₂. Further increase in dissolved S is prevented by the buffering effects of either sulphide at low <em>f</em>O₂ or anhydrite at high <em>f</em>O₂. Modelling shows that the observed CO₂/SO₂ and H₂O/SO₂ ratios of volcanic gas emissions during the eruption imply a pre-existing &gt;5 wt% exsolved fluid in the reservoir, with <em>f</em>S₂ at ∼0.1 MPa at <em>f</em>O₂ above NNO. Our work confirms that basaltic magmas may coexist with a significant amount of excess fluid which in turn holds an important part of the sulphur budget emitted to the atmosphere.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"456 ","pages":"Article 108219"},"PeriodicalIF":2.4,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conduit armouring preceding explosive activity at an andesitic stratovolcano, an example from Taranaki Mounga, New Zealand","authors":"Henry Hoult ,&nbsp;Ben M. Kennedy ,&nbsp;Alexander R.L. Nichols ,&nbsp;Shane Cronin ,&nbsp;Leighton Watson","doi":"10.1016/j.jvolgeores.2024.108214","DOIUrl":"10.1016/j.jvolgeores.2024.108214","url":null,"abstract":"<div><div>The strength and permeability of volcanic conduits can directly influence eruption dynamics via moderating the outgassing of ascending magma and the density of eruption plumes. Lithic clasts in pyroclastic ejecta can be used to understand the dynamic evolution of conduit walls because they are incorporated into the ascending melt-gas-particle mixture during volcanic eruptions. We examine the 1655 CE Burrell eruption of Taranaki Mounga, which transitioned from effusive activity to an explosive sub-Plinian phase and ended in unsteady columns. This episode was followed by a series of effusive eruptions of lower explosivity. Using textural analysis and physical properties, we distinguish five dominant lithic clast types within Burrell deposits that represent different regions of the shallow conduit and vent. Lithic types 1–3 represent juvenile (‘intrusive cognate’) and older (‘intrusive accessory’) conduit-filling plug materials. Lithic type 4 represents juvenile (‘extrusive cognate’) vent-filling lava dome extruded at the eruption onset, while Type 5 lithics (‘extrusive cognate’) represent sintered/compacted cognate material from the shallow vent accumulated during transitions in eruptive style. Crystalline andesite lithics (type 1) show a microlite-dominated groundmass. Hydrothermally altered andesite lithics (type 2) show breakdown of phenocrysts and increased seismic velocity relative to type 1 lithics. Brecciated andesite lithics (type 3) comprise fractured and sintered clasts of crystalline andesite. Glassy andesite lithics (type 4) show sub-rounded vesicles and glass-hosted microlites. Banded vitrophyre lithics (type 5) show bands of varying vesicularity, crystallinity and clast load. Physical property data reveals porosity, fracturing, sintering and alteration extent dictate dynamic changes in conduit permeability and potentially strength. Our results show how, during the explosive phase of the Burrell eruption, the conduit was lined with juvenile and remnant shallow plug material that was variably fractured, sintered and altered before being eroded and ejected. Comparison with previous work on Taranaki and dome-plug material from around the world shows how fracturing and sintering of conduit walls, combined with lining with dense juvenile material, cause overall permeability reduction and strengthening of the conduit. This inhibits outgassing and preserves conduit structure, facilitating the transition to explosive activity and the establishment of a stable eruption column.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108214"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Volcanic tremor associated with successive gas emission activity at a boiling pool: Analyses of seismic array and visible image data recorded at Iwo-Yama in Kirishima Volcanic complex, Japan","authors":"Masato Hata ,&nbsp;Takeshi Nishimura ,&nbsp;Takeshi Matsushima ,&nbsp;Tomofumi Kozono ,&nbsp;Tsutomu Nagatsuma ,&nbsp;Ken T. Murata ,&nbsp;Kazutaka Kikuta ,&nbsp;Dan Muramatsu ,&nbsp;Hisashi Nakahara","doi":"10.1016/j.jvolgeores.2024.108212","DOIUrl":"10.1016/j.jvolgeores.2024.108212","url":null,"abstract":"<div><div>Volcanic tremors are often observed during volcanic activity and volcanic eruptions, and their generation processes provide clues for understanding volcanic fluid activity underground and eruption dynamics. However, tremors are characterized by continuous oscillations that mask P- and S-waves; hence few studies have precisely located the source, which is the most fundamental information for understanding the generation mechanism. In this study, we focus on volcanic tremors excited by continuous gas emissions occurring at a vent called Y2a in Iwo-Yama, the Kirishima Volcanic Complex, Japan, to clarify the source process of the tremor as well as gas emission activity. We simultaneously observed the volcanic tremor by deploying a small aperture array consisting of six seismometers and the gas emission activity by using a newly developed visual IoT system that can be operated without commercial electricity. MUSIC analysis locates the tremor at depths ranging from the ground surface to approximately 200 m beneath the Y2a and Y2b vents, which are approximately 30 m apart, for approximately four months from November 2021 to February 2022. The source locations of the tremors in the 2 Hz (1.2–2.6 Hz), 4 Hz (3–4 Hz), and 5 Hz (4–5.5 Hz) ranges show some differences and changes with time. The source location tends to become deeper when the 2 Hz amplitude is large. The infrasound generated by gas emission activity is dominant in the tremor signals, which are recognized in the wave propagation velocity with an acoustic velocity of 330 m/s when the 2 Hz amplitude is small. The visual IoT system succeeded in detecting long-term changes in the gas emission activity, and we found that the 2 Hz amplitude of tremor was well correlated with the amount of hot water in the boiling pool of Y2a, which was controlled by precipitation and evaporation during non-rainy days. From these observations, we infer that the volcanic tremor is generated by resonance of volcanic gas and hot water in a crack-like structure beneath Y2a. The resonance was triggered by the counterforces of the gas emissions in the boiling pool, and the infrasound was dominant during periods of hot water depletion in the boiling pool. Temporal changes in the source depths may be caused by changes in the fluid properties, configuration of the resonator and/or the strengths of the underground sources and infrasound. Our simultaneous observations of seismic array and visual IoT system clarify that even the continuous gas emission activity that looks stable is controlled by external sources such as precipitation.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108212"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spread and frequency of explosive silicic volcanism of the Carpathian-Pannonian Region during Early Miocene: Clues from the SW Pannonian Basin and the Dinarides","authors":"Mihovil Brlek ,&nbsp;Nina Trinajstić ,&nbsp;Sean P. Gaynor ,&nbsp;Steffen Kutterolf ,&nbsp;Folkmar Hauff ,&nbsp;Julie Schindlbeck-Belo ,&nbsp;Sanja Šuica ,&nbsp;Kuo-Lung Wang ,&nbsp;Hao-Yang Lee ,&nbsp;Elena Watts ,&nbsp;Svetoslav V. Georgiev ,&nbsp;Vlatko Brčić ,&nbsp;Marko Špelić ,&nbsp;Ivan Mišur ,&nbsp;Duje Kukoč ,&nbsp;Blair Schoene ,&nbsp;Réka Lukács","doi":"10.1016/j.jvolgeores.2024.108215","DOIUrl":"10.1016/j.jvolgeores.2024.108215","url":null,"abstract":"<div><div>Explosive silicic volcanism of the Carpathian-Pannonian Region (CPR) is increasingly recognized as the primary source of tephra across the Alpine-Mediterranean region during the Early and Middle Miocene. However, the tephrostratigraphic framework for this period of volcanic activity is still incomplete. We present new multi-proxy data from Lower Miocene ignimbrites and tephra fallout deposits from the southwestern CPR and the Dinaride Lake System and integrate them into existing datasets to better resolve the regional extent and scale of these eruptions of the CPR. Volcanic glass geochemistry indicates distal fallout tuffs deposited in the Sinj Basin are correlative with the proximal Ostoros ignimbrites from the Bükkalja Volcanic Field, indicative of regionally extensive volcanism at 17.295 ± 0.028 Ma, based on CA-ID-TIMS U<img>Pb zircon geochronology. Based on integrated tephrostratigraphic data, newly identified 17.064 ± 0.010 Ma massive rhyolitic ignimbrite deposits from the Kalnik Volcaniclastic Complex located in the southwestern CPR are correlative with the 17.062 ± 0.010 Ma Mangó massive ignimbrite found in the Bükkalja Volcanic Field located in the northern CPR. Based on these new observations of its potential areal distribution and estimated thicknesses, these two widespread ∼17.1 Ma ignimbrites represent intermediate to large caldera-forming ignimbrites, larger than previously suggested. Finally, volcanic glass geochemistry of fallout deposits from the Dinaridic Sinj and Livno-Tomislavgrad Basins have similar volcanic glass geochemistry as the rhyolitic pumices from the lowermost part of the Bogács ignimbrite unit of the Bükkalja Volcanic Field. However, high-precision geochronology indicates that these distal ashfalls were deposited at 16.9567 ± 0.0074 Ma, significantly predating the 16.824 ± 0.028 Ma emplacement of the fiamme-bearing part of the Bogács ignimbrite. These distinct ages suggest that the Bogács unit represents multiple eruptive events and indicating that further work is required to deconvolve this portion of the CPR volcanic record. Together, these data suggest that large volume CPR ignimbrite volcanism was more frequent and widespread than previously understood, enhancing the existing volcanic framework and history of the source region for this time period.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108215"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Volcanomagnetic signals related to the 2021 Tajogaite volcanic eruption in the Cumbre Vieja rift (La Palma, Canary Islands)” [Journal of Volcanology and Geothermal Research 455 (2024) 108200]","authors":"Isabel Blanco-Montenegro ,&nbsp;José Arnoso ,&nbsp;Nieves Sánchez ,&nbsp;Fuensanta G. Montesinos ,&nbsp;David Gómez-Ortiz ,&nbsp;Iacopo Nicolosi ,&nbsp;Emilio Vélez ,&nbsp;Maite Benavent","doi":"10.1016/j.jvolgeores.2024.108213","DOIUrl":"10.1016/j.jvolgeores.2024.108213","url":null,"abstract":"","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108213"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Melt viscosity tracks the volcanic and magmatic evolution of the 2021 Tajogaite eruption, La Palma (Canary Islands)","authors":"Arianna Soldati ,&nbsp;Corrado Cimarelli ,&nbsp;Ulrich Kueppers ,&nbsp;Francisco Cáceres ,&nbsp;Dirk Müller ,&nbsp;Matthew Pankhurst ,&nbsp;Jane H. Scarrow ,&nbsp;Nemesio Perez ,&nbsp;Donald B. Dingwell","doi":"10.1016/j.jvolgeores.2024.108210","DOIUrl":"10.1016/j.jvolgeores.2024.108210","url":null,"abstract":"<div><div>After more than 50 years of repose, on September 19th, 2021, a volcanic eruption began at the Cumbre Vieja ridge on La Palma, Canary Islands. The combined effusive and explosive activity generated a &gt; 12 km² lava flow field with a new cone nearly 200 m higher than pre-eruptive topography and a vast tephra blanket. The immediate impact was locally devastating, destroying nearly 2000 buildings, blocking two main and numerous secondary roads, and inundating high-value agricultural land.</div><div>The hybrid nature of the eruption and the observed variations in eruption intensity motivated a thorough investigation of bulk liquid viscosity at high temporal resolution. Collection of 82 lava samples was achieved at a near daily resolution over the course of the 85-day-long event (through the end of the eruption on December 13th, 2021). All the samples were remelted, and liquid viscosity was measured in a concentric cylinder viscometer from 1490 °C down to incipient crystallization temperatures. These data constitute the highest temporal resolution viscosity dataset obtained for an eruptive sequence to date.</div><div>A tripartite viscosity pattern is identified at isothermal conditions: 1) during the fissure opening and establishing stage (days 1–20) a linear decrease in melt viscosity occurred; 2) during most of the eruption duration (days 21–70) viscosity was constant and 3) from day 70 until the end of the eruption viscosity increased again. We interpret this pattern as magma being extracted from different parts of the plumbing system over the course of the eruption. Accordingly, we show that viscosity time series can help shed light on some of the complexities of volcanic plumbing system. Additionally, the presented results highlight the monitoring potential of the viscosity assessment approach, specifically in regard to forecasting eruption behavior using direct information about magma mobility and detecting changes in magmatic plumbing system dynamics.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108210"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Melt embayments record multi-stage magma decompression histories","authors":"Behnaz Hosseini,&nbsp;Madison Myers","doi":"10.1016/j.jvolgeores.2024.108211","DOIUrl":"10.1016/j.jvolgeores.2024.108211","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Over the last decade, the melt embayment has proven its merit as a robust petrological tool capable of recording magma decompression rates for explosive eruptions. However, the models developed and applied to extract this information from embayments have not accounted for the complexity and nonlinearity of magma flow in the conduit. We present Embayment Decompression in Two Stages (EDiTS): a numerical model for extracting magma decompression rates from measured volatile diffusion profiles preserved in crystal-hosted embayments, approximating magma acceleration using two constant-rate decompression paths. This model solves for three unknown parameters: initial (deeper) and final (shallower) decompression rates, as well as the pressure where a transition occurs. We successfully benchmark EDiTS against existing numerical diffusion models, and use controlled multi-stage decompression experiments on natural quartz-hosted embayments to test the ability of our model to recover known decompression paths. We find that EDiTS is able to closely approximate the known two-stage path in the mixed-volatile (H&lt;sub&gt;2&lt;/sub&gt;O + CO&lt;sub&gt;2&lt;/sub&gt;) experiment, while a constant-rate modeling approach is unable to simultaneously fit H&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt; gradients. However, in the H&lt;sub&gt;2&lt;/sub&gt;O-saturated experiment, there is no unique solution to the resulting gradient, with both constant-rate and two-stage models reproducing the measured profile, and EDiTS notably overestimating the known total ascent time by several hours. Using decompression experiments, we show that constant-rate models can provide misleadingly good fits to embayment H&lt;sub&gt;2&lt;/sub&gt;O gradients produced by more complex decompression histories, and thus the measurement and modeling of multiple diffusing species, when available, can provide crucial constraints. We then apply EDiTS to re-evaluate mixed-volatile embayment datasets from explosive silicic arc and caldera-forming eruptions from five volcanic centers (Yellowstone, WY, USA; Valles, NM, USA; Long Valley, CA, USA; Taupo, NZ; Mount St. Helens, WA, USA). In contrast to the minutes to hours of total ascent time extracted from embayment volatile profiles using constant-rate models, our two-stage model resolves slower initial ascent times that span 3.5–11 h. Final ascent rates are 1–2 orders of magnitude faster than the initial extracted rates, in agreement with theoretical conduit flow model predictions. Reassessment of embayments from the May 18th, 1980 eruption of Mount St. Helens results in an initial stage of ascent consistent with the timing of magma arrival at the surface from the seismically-inferred storage region (7–9 km) ∼3.5 h after the initial blast, and a final stage of ascent (&lt;1–5 min) in close agreement with time-integrated bubble number densities. Our combined numerical and experimental results, and reevaluation of natural datasets, suggest that, with the application of advanced models, the melt embayment can ","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"456 ","pages":"Article 108211"},"PeriodicalIF":2.4,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}